The present invention relates to a process for the manufacture of a protecting and immobilising element of the mattress-like type, and to a mattress-like element so obtained, and in particular to a process for the manufacture of a protecting and immobilising mattress for underwater pipes.
It is known from the document U.S. Pat. No. 4,477,206, belonging to the same applicant, to use parallelepipedal flexible protecting elements for immobilising and protecting underwater pipes. Those elements comprise a flexible outer covering which covers a gabion produced from metal material and filled with a mixture composed of bitumen, sand and stones or pebbles. The protecting elements, once manufactured, are to be lowered into water, at the location of the pipes to be protected, by means of handling machines, such as cranes, mechanical arms and the like.
In order to facilitate such positioning, processes are known for the manufacture of mattress-like protecting elements comprising support elements which, in use, facilitate the handling thereof. Document EP0881334, in the name of Giuseppe Sarti and C., illustrates a process for the manufacture of a mattress-like flexible component comprising the stages of covering the chamber of a mould with a cover, positioning inside the chamber a reinforcement of wire netting lying in a plane parallel with the base of the chamber, introducing into the chamber a filling material, which is premixed at high temperature and is composed of an aggregate having dimensions such as to pass through the meshes of the netting until the reinforcement is incorporated, and covering the filling material with the cover.
The object of the present invention is to provide a process for the manufacture of protecting elements of the mattress-like type in a rapid, efficient and economical manner which thus permits a high degree of saving in terms of installation costs and time.
A further object of the present invention is to optimise the stages of the process for the manufacture of a protecting element of the mattress-like type which is easy to handle and is adaptable to different conditions of use.
In order to achieve the objects indicated above, the present invention relates to a process for the manufacture of protecting elements of the mattress-like type, comprising the stages of providing containing means; providing a layer of flexible material and arranging it inside the containing means, with the peripheral edges of the flexible layer protruding from the containing means; arranging anchoring means and a first netting structure inside the containing means, the netting structure being in direct contact with the flexible layer and the anchoring means passing through the netting structure at predetermined positions; filling the containing means with a filling material comprising solid and/or fluid elements; superposing a second netting structure on the filling material, and superposing, at least partially, the peripheral edges of the flexible layer in such a manner as to produce a closed cover from which the ends of the anchoring means protrude.
One of the main advantages of the present invention is that it provides a process for the manufacture of protecting elements of the mattress-like type, which, by reducing the number of stages necessary compared with the known processes, is rapid and efficient and, at the same time, preserves unchanged all of the characteristics of solidity and flexibility present in the protecting and immobilising elements of known type.
A further advantage of the present invention resides in the use of a filling material which comprises solid elements which are readily available even in situ, and the form and dimensions of which are not limited, as long as the characteristics of resilience of the mattress-like element can be maintained.
Another advantage of the present invention consists in the particular and innovative form of the anchoring means which facilitate the homogeneous distribution of the filling material inside the mould, preventing impurities, discontinuity and residual cavities, and increasing the resilient characteristics of the mattress-like element.